Plugging machines

ABSTRACT

Apparatus for inserting fibrous plugs into the ends of pipettes comprises means for successively severing lengths from a fibrous strand (usually cotton wool roving) the means having a knife edge, and a relatively movable roller arranged to roll along the knife edge and cut the strand. Preferably the fibrous strand is fed by increments vertically downwardly under gravity towards the severing means, so as to avoid the formation of fluff which occurs when pneumatic feeders are used.

United States Patent Cowley et al. Oct. 7, 1975 [54] PLUGGING MACHINES 3,017,795 1/1962 Joa 83/129 3,138,985 6/1964 Mills....-, 83/510 x [751 Invemors: Rmald Cowley; Regma'd 3,157,012 11/1964 Shellman et al. 53/115 Hallwood, both of Barking; Norma" 3,460,315 8/1969 Roeck 53 115 Lockwood, Rayleigh, all of England Assigneei John Poulten Limited, Barking, Primary Examiner-Travis S. McGehee England Assistant Examiner-Horace M. Culver Oct. Attorney, Agent, or Firm-Brady, OBoyle & Gates [21] Appl. No.: 407,483

[57] ABSTRACT [30] Foreign Application Priority Data Apparatus for inserting fibrous plugs into the ends of Nov. 10, 1972 United Kingdom 52144/72 pipettes comprises means for successively severing 1 lengths from a fibrous strand (usually cotton wool rov- [52] US. Cl. 53/115; 83/129; 83/510; ing) the means having a knife edge, and a relatively 53/123 movable roller arranged to roll along the knife edge B65B 6 B653 55/ 0 and cut the strand. Preferably the fibrous strand is fed Field Of Search 3, 0, by increments vertically downwardly under gravity 53/264, 319, 321, 328; 83/129, 130, 510 towards the severing means, so as to avoid the formation of fluff which occurs when pneumatic feeders are [56] References Cited used.

UNITED STATES PATENTS o 7 2,764,860 10/1956 Harrison et a1. 53/115 x 4 Clams 5 'l F'gures Sheet 1 of 4 US. Patent Oct. 7,1975

15.9mm Oct.7,1975 Sheet20f4 3,910,010

FlG.3

US. Patent Oct. 7,1975 Sheet 3 of4 3,910,010 7 FIG. L.

PLUGGING MACHINES The invention relates to a machine for inserting a plug of a fibrous material into the end of a hollow member such as a pipe, and more particularly to a machine for inserting a plug of roving into the end of a pipette.

It is often desirable to insert fibrous plugs, usually of cotton wool, into the ends of pipettes before they are used, either to prevent contamination of the liquid in the pipette or to prevent the liquid from being sucked into the users mouth. Until now such plugs have often been inserted by hand which when large numbers or pipettes are to be plugged is extremely time'consuming. Machinesare known for automatically inserting plugs into the ends of pipettes but the known machines tend to suffer from problems associated with the fact that cotton wool tends to form fluff when it is conveyed to the cutting position and with the fact that cotton wool is difficult to cut.

It is an object of the invention to provide a machine for inserting a plug ofa roving into the end of a pipe e.g. a pipette which avoids or mitigates against the disadvantages set-out above.

According to the invention there is provided apparatus for inserting a fibrous plug into the end of a hollow member, comprising means for severing a portion of a fibrous strand which is to form the plug from a length thereof, the means having a knife edge, a relatively movable roller arranged to roll along the knife edge and means urging the roller into contact with the knife edge.

From another aspect the inventionprovides apparatus as defined above comprising means for feeding the fibrous strand by increments vertically downwardly towards the severing means. In previous machines the roving has often been conveyed by shuttle, pneumatic devices or gears. In view of the nature of cotton wool these methods lead to the production of large amounts of fluff. The arrangement defined above in which the roving is fed vertically downwards under gravity avoids this disadvantage. Preferably means are provided for clamping the roving against movement during the severing operation. Advantageously means are also provided for moving the end of the roving laterally away from the severing means after each severing operation.

The machine preferably comprising means for inserting the cut portion of roving into the end of the pipe comprising a needle-like probe mounted for reciprocation into and out of the end of the tube. V

The means for reciprocating the probe and for feeding the roving vertically downwards preferably comprises pneumatically actuated rams.

The invention is diagrammatically illustrated, by way of example, in the accompanying drawings in which:

FIG. 1 is a side elevation of a pipette plugging machine;

FIG. 2 is a front end elevation of the machine shown in FIG. 1; 7

FIG. 3 is an exploded perspective view ofpart of the machine;

FIG. 4 is a perspective view of another part of the machine, and

FIG. 5 shows the pneumatic circuit of the machine.

The pipette plugging machine shown in the drawings is a hand operated machine intended for laboratory use or the like. The material which forms the plugs is preferably cotton wool which has been loosely spun to form a continuous roving which can be fed to the machine from a'bobbin. A

The machine comprises a frame having two opposed members 22 and 23 respectively which are formed with corresponding oppositely arranged slots 24, which together define a generally horizontal track. A carriage 6 having pivoted thereon three horizontally disposed rollers 26, 27, 28 is arranged so that the rollers engage the slots 24 in the machine frame whereby the carriage can move along the track-in a horizontaldirection. A first pneumatic ram 5 is stationarily mounted on the machine frame and the piston rod 25 thereof is operatively connected to the carriage 6 so as to move the carriage along the track when the ram is actuated. Depending from the carriage is amember 29 carrying a generally horizontally disposed needle-like prove 7 which is aligned in the direction of movement of the carriage. A pipette block 30 is disposed on the machine frame at the forward end of the range of movement of the carriage and has an aperture 2 which is concentric with the axis of the probe 7 so that when the carriage is moved to its fully forward position the probe enters the aperture. Mounted on the member 23 is a knife bar 13 of square crosssection and having a cutting edge 31 aligned with the direction of movement of the carriage. The disposition of the roller 28 on the carriage 6 is such that when the carriage is advanced the roller runs along the knife edge. The roller 26 is mounted opposite to the roller 28 and in Contact therewith so as to prevent movement of the roller 28 away from the knife edge.

Mounted on the track member 23 and above the track slot 24 is a dislodging arm 12 which is pivoted on the track member 23 for movement in a horizontal plane. The dislodging arm extends generally in the direction of motion of the carriage. The forward end of the dislodging arm is disposed above the knife edge and carried a guide member 32 in the form of a U-shaped member. The forward end of the carriage is formed with a plate-like guide member 33 which co-operates with the guide member 32 to fonn a closed guide channel. The disposition of the parts 32 and 33 is such that the four sides of the guide channel mate when the carriageis in its fully retracted position. The carriage and the disloding arm carry cooperating pins 11 and 34 respectively whereby when the carriage is in its fully retracted position the arm is caused to swing away from the knife edge. Forward motion of the carriage causes the knife engaging roller 28 to engage an abutment 35 on the arm, which in this case is an extension of the guide member 32, so as to swing the arm 12 towards the knife edge. I

Mounted on the member 23 above the carriage are a pair of feed wheels 20 and 21 respectively. The feed wheel 20 is stationarily but rotatably mounted on the frame but the feed wheel 21 is mounted on a spring biased arm 36 so as to be urged against the drive wheel 20. The feed wheel 20 is flanged and part of the feed wheel 2l is normally disposed within the flanged portion of the wheel 20. The feed wheel 20 is connected via a ratchet mechanism 19 to an arm 18 whereby the wheel may be rotated in one direction by a second pneumatic ram 17 which is trunnion mounted on the machine frame and which has a piston rod 37 con nected to the arm 18.

Mounted on the underside of the member 23 below the dislodging arm 12 for pivotal movement in a horizontal plane is a clamping arm 9 having at its forward end a clamping member 40, the clamping arm being spring biased to hold the clamping member against a plate 41 disposed below the knife edge. The clamping arm carries a pin 38 which cooperates with a pin 10 on the carriage when the carriage is fully retracted to move the clamping member 40 away from the plate 41.

The machine frame also has mounted thereon first and second valves 4 and 16 (e.g. five port valves) which cooperate respectively with the first and second pneumatic rams 5 and 17. The actuator 3 for the first valve 4 is disposed immediately behind the pipette block 30. The actuator 15 for'the second valve 16 is disposed above the carriage and is arranged for cooperation with a pin 14 on the carriage.

The arrangement is such that insertion of a pipette into the bore 2 in the pipette block actuates the valve 4 to cause the advance of the carriage, and retraction of the carriage on removal of the pipette from the pipette block causes the pin 14 on the carriage to engage the actuator 15 for the second valve which in turn causes the second pneumatic ram 17 to rotate the feed wheels. The ratchet mechanism 19 ensures that no counter-rotation of the feed wheels takes place when the ram 17 retracts.

in operation roving is loaded into the machine by pulling forward a lever 1 which is carried by the arm 36 to disengage the feed roller 21 from the roller 20. The roving is then inserted between the feed rollers and is fed down through the guide channel formed by the members 32 and 33. The lever l is then released so that the wheels grip the roving and the air supply to the machine is switched on. A pipette 42 is then inserted into the aperture 2 to engage the arm 3 which causes the carriage 6 carrying the probe 7 and cutting roller 28 to advance to the forward position. In doing so the pin on the carriage becomes disengaged from the pin on the clamping arm which allows a clamping member 40 on the forward end of the arm 9 to move over and clamp the roving against the plate on the machine frame. The roller 28 then cuts the roving where it crosses the knife edge and the probe 7 pushes the cut portion of the roving into the end of the pipette to form a plug therein.

Withdrawal of the pipette from the pipette block permits the arm 3 to return to its rest position thus causing the carriage to return to its retracted position. Backward movement of the carriage 6 causes the pin 10 to engage the pin 38 on the roving clamp arm 9 which thus moves to its disengaged position. Also the pin 11 on the carriage 6 engages with the pin 34 on the arm 12 which moves over to dislodge the end of the roving from the cutting bar 13. Afterwards the pin 14 on the carriage 6 engages with the roller actuator 15 on the arm of the valve 16 which operates ram 17 to rotate the feed wheel 20, taking with it the free rolling wheel 21. The roving sandwiched between the feed wheels 20 and 21 is thus automatically fed down to the required amount, ready for the next pipette to be plugged.

The pneumatic circuit is illustrated with reference to FIG. 5 of the drawings. Air under pressure is supplied to the machine through an on/off switch and via a pressure regulator. Upstream of the regulator is disposed a high pressure feed off to a de-plugging device by means of which plugs of roving can be removed from pipettes if desired.

The sequence of operation of the pneumatic circuit is as follows.

Pressing a pipette 42 against the actuating arm 3 of valve 4 causes air to be supplied by the valve to the front end of carriage ram 5 thus causing it to instroke, and in doing so causing the carriage to advance. The pin 14 on the carriage having moved away from the roller arm actuator 15 of the valve 16 supplies air to the front end of ratchet ram 17 which instrokes and resets the ratchet.

When the pipette is withdrawn, the actuating arm 3 moves to its rest position and shuts off the air supply to the front of the carriage ram and instead supplies air to the rear end of the carriage ram 5, causing it to outstroke and in so doing moving the carriage to its fully retracted position. In moving into this position the carriage strikes against the roller actuator 15 and in doing so shuts off the air supply to the front of the ratchet ram and supplies air to the rear end of the ram thus causing it to outstroke and rotate the feed wheels 20, 21.

We have discovered that where cotton wool is to be inserted into the end of a pipette it is helpful first to spin the cotton wool to form a loose roving. In this way the bulk supply of the plugging material can be considerably reduced in size and can be conveniently mounted on a bobbin.

We claim:

1. Apparatus for inserting a fibrous plug into the end of a hollow member comprising severing means, means for feeding a fibrous strand incrementally and vertically downwardly toward said severing means for cutting plug lengths from the end of the strand, said severing means including a knife edge and a roller, a reciprocatable carriage movable relative to said knife edge, said roller connected to said reciprocatable carriage and connected to roll along said knife edge to sever a plug length from the end of the strand disposed therebetween, a needle-like probe connected to said carriage and adapted to contact a severed plug length of fibrous material and to insert it into the end of the hollow member, means connected for reciprocating the carriage, means for clamping the end of the strand against movement during severing by said roller and knife edge, and means for moving the end of the fibrous strand laterally away from the severing means after a plug length has been cut away therefrom, the means for moving the end of the strand being connected for operation by the reciprocatable carriage.

2. Apparatus according to claim 1, wherein said means for clamping the end of the fibrous strand against movement during severing is connected for operation by the reciprocating carriage.

3. Apparatus as set forth in claim 1 in which said means for feeding the fibrous strand vertically downwardly includes a pneumatically actuated ram.

4. Apparatus as set forth in claim 1 in which said knife edge forms part of a track along which said carriagc is reciprocatable. 

1. Apparatus for inserting a fibrous plug into the end of a hollow member comprising severing means, means for feeding a fibrous strand incrementally and vertically downwardly toward said severing means for cutting plug lengths from the end of the strand, said severing means including a knife edge and a roller, a reciprocatable carriage movable relative to said knife edge, said roller connected to said reciprocatable carriage and connected to roll along said knife edge to sever a plug length from the end of the strand disposed therebetween, a needle-like probe connected to said carriage and adapted to contact a severed plug length of fibrous material and to insert it into the end of the hollow member, means connected for reciprocating the carriage, means for clamping the end of the strand against movement during severing by said roller and knife edge, and means for moving the end of the fibrous strand laterally away from the severing means after a plug length has been cut away therefrom, the means for moving the end of the strand being connected for operation by the reciprocatable carriage.
 2. Apparatus according to claim 1, wherein said means for clamping the end of the fibrous strand against movement during severing is connected for operation by the reciprocating carriage.
 3. Apparatus as set forth in claim 1 in which said means for feeding the fibrous strand vertically downwardly includes a pneumatically actuated ram.
 4. Apparatus as set forth in claim 1 in which said knife edge forms part of a track along which said carriage is reciprocatable. 